Fixed #32208 -- Allowed adding lazy() objects.

Co-authored-by: Claude Paroz <claude@2xlibre.net>

django/utils/functional.py

@@ -176,6 +176,12 @@ def lazy(func, *resultclasses):
                 return str(self) % rhs
             return self.__cast() % rhs
 
+        def __add__(self, other):
+            return self.__cast() + other
+
+        def __radd__(self, other):
+            return other + self.__cast()
+
         def __deepcopy__(self, memo):
             # Instances of this class are effectively immutable. It's just a
             # collection of functions. So we don't need to do anything